1. Field of the Invention
This invention resides in a polymerization process which is catalyzed by oxyanions, and to polymers produced thereby.
2. Background
U.S. Pat. Nos. 4,414,372; 4,417,034; 4,524,196; and 4,508,880 and commonly assigned U.S. patent applications Ser. Nos. 660,588 and 660,589, filed Oct. 18, 1984; 673,926, filed Nov. 21, 1984; and 676,099, filed Nov. 29, 1984, hereinafteer referred to as "the aforesaid patents and applications", disclose processes for polymerizing polar monomers to "living" polymers. In certain of the aforesaid patents and applications there is disclosed a process of preparing a "living" polymer, the process comprising contacting under polymerizing conditions at least one polar monomer with (i) a polymerization initiator compound comprising a tetracoordinate metal selected from Si, Ge and Sn having at least one activating substituent or activating diradical attached thereto, and (ii) a suitable co-catalyst, the polymerization being characterized by the presence, in the growing and in the grown polymer, of a moiety containing said metal at "living" ends and said activating substituent or diradical, or a tautomer thereof, at "nonliving" ends of said polymer, the initiator optionally having one or more substituents that are inert under polymerizing conditions. The aforesaid patents and applications also disclose processes of polymerizing the monomer selected from the group consisting of CH.sub.2 .dbd.C(Y)X, ##STR1## and mixtures thereof wherein: X is --CN, --CH.dbd.CHC(O)X' or --C(O)X';
Y is --H, --CH.sub.3, --CN or --CO.sub.2 R, provided, however, when X is --CH.dbd.CHC(O)X', Y is --H or --CH.sub.3 ; PA0 X' is --OSi(R.sup.1).sub.3, --R, --OR or --NR'R"; each R.sup.1, independently, is a hydrocarbyl radical which is an aliphatic, alicyclic, aromatic or mixed aliphatic-aromatic radical containing up to 20 carbon atoms; PA0 R is a hydrocarbyl radical which is an aliphatic, alicyclic, aromatic or mixed aliphatic-aromatic radical containing up to 20 carbon atoms, optionally containing one or more ether oxygen atoms within aliphatic segments thereof and optionally containing one or more functional substituents that are unreactive under polymerizing conditions; and PA0 each of R' and R" is independently selected from C.sub.1-4 alkyl PA0 (i) the initiator of the formula (R.sup.1).sub.3 MZ wherein: PA0 (a) R.sup.1 is H, provided that at least one R.sup.1 group is not H; and/or PA0 (b) R is a polymeric radical containing at least 20 carbon atoms and optionally containing one or more ether oxygen atoms within aliphatic segments thereof and optionally containing one or more functional substituents that are unreactive under polymerizing conditions; and/or PA0 (c) at least one of any R group in the monomer contains one or more reactive substituents of the formula --Z'(O)C--C(Y.sup.1).dbd.CH.sub.2 wherein Y.sup.1 is H or CH.sub.3 and Z' is as defined above; and/or PA0 (d) the initiator is of the formula (R.sup.1).sub.2 M(Z.sup.1).sub.2 or O[M(R.sup.1).sub.2 Z.sup.1 ].sub.2 wherein R.sup.1 and M are as defined above and Z.sup.1 is ##STR4## wherein X', R.sup.2 and R.sup.3 are as defined above; and/or (e) at least one of any R, R.sup.2 and R.sup.3 in the initiator contains one or more initiating substituents of the formula --Z.sup.2 --M(R.sup.1).sub.3 wherein PA0 (g) R.sup.2 and R.sup.3 taken together are ##STR7## provided, however, Z is ##STR8## and/or Z.sup.2 is ##STR9## and/or (h) X' and either R.sup.2 or R.sup.3 taken together are ##STR10## provided, however, Z is ##STR11## and/or Z.sup.2 is ##STR12##
by contacting the one or more monomers under polymerizing conditions with:
R.sup.1 is as defined above; PA1 Z is an activating substituent selected from the group consisting of ##STR2## and mixtures thereof wherein: X' is as defined above for the monomer; each of R.sup.2 and R.sup.3 is independently selected from H and hydrocarbyl, defined as for R above; PA1 Z' is O or NR' wherein R' is as defined above; PA1 m is 2, 3 or 4; PA1 n is 3, 4 or 5; and PA1 M is Si, Sn, or Ge, provided, however, when Z is ##STR3## M is Sn or Ge; and (ii) a co-catalyst which is a source of bifluoride ions HF.sub.2.sup.-, or a source of fluoride, cyanide or azide ions or a suitable Lewis acid, for example, zinc chloride, bromide or iodide, boron trifluoride, alkylaluminum oxide or an alkylaluminum chloride, PA1 M and R.sup.1 are as defined above; and PA1 Z.sup.2 is a diradical selected from the group consisting of ##STR5## and mixtures thereof, wherein R.sup.2, R.sup.3, X', Z', m and n are as defined above, provided, however, when Z.sup.2 is ##STR6## M is Sn or Ge; and/or (f) Z is selected from the group consisting of --SR, --OP(NR'R").sub.2, --OP(OR.sup.1).sub.2, --OP[OSi(R.sup.1).sub.3 ].sub.2 and mixtures thereof, wherein R, R.sup.1, R' and R" are as defined above; and/or
to produce "living" polymer having repeat units of the one or more monomers, said processes further characterized in that:
As further disclosed in the aforesaid patents and applications, although these processes resemble anionic polymerization, there are significant differences which have commercial significance. These differences include the ability to copolymerize methacrylate and acrylate monomers, or combinations of acrylate monomers, for example, ethyl and sorbyl acrylates, to relatively monodisperse copolymers. Such copolymers are difficult or impossible to obtain by known processes such as anionic polymerization or free-radical polymerization. Moreover, whereas anionic polymerization processes which provide relatively monodisperse polymers are carried out at low temperatures, usually well below -10.degree. C., which require expensive refrigeration equipment for commercial operation, the polymerization processes of the patents are operable over a wide temperature range, from about -100.degree. C. to about 150.degree. C., and they are conveniently operable with many commercially important monomers at about ambient temperatures.
Commonly assigned copending application Ser. No. 618,736, filed June 8, 1984, and allowed Sept. 9, 1985, discloses certain tris(disubstituted amino)sulfonium perfluoroalkoxides, including tris(dimethylamino)-sulfonium trifluoromethoxide, and the use of this compound as a catalyst in the polymerization processes of U.S. Pat. Nos. 4,414,372 and 4,417,034. Such use is outside the scope of the invention which is disclosed and claimed hereinbelow, since tris(dimethylamino)-sulfonium trifluoromethoxide is not a salt comprising an oxyanion which can form a conjugate acid having the requisite pKa.
It is an object of this invention to provide additional catalysts (referred to in the aforesaid patents and applications as "co-catalysts") which can be used in the processes disclosed in the aforesaid patents and applications. Another object is to provide processes which are similar to the processes disclosed in the aforesaid patents and applications in that they can be carried out with the same monomers and initiators to produce the same "living" polymers, but differing in the type of catalyst used. Still another object is to provide catalysts which are suitable in the processes of the aforesaid patents and applications but which are inoperable in conventional art-recognized anionic processes for polymerizing the same type of monomer. A further object is to provide such catalysts which are readily and economically preparable. These and other objects will be apparent from the disclosure that follows.